id: CVE-2023-4911

info:
  name: Looney Tunables Linux - Local Privilege Escalation
  author: nybble04
  severity: high
  description: |
    A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES environment variable. This issue could allow a local attacker to use maliciously crafted GLIBC_TUNABLES environment variables when launching binaries with SUID permission to execute code with elevated privileges.
  reference:
    - https://nvd.nist.gov/vuln/detail/CVE-2023-4911
    - https://www.qualys.com/2023/10/03/cve-2023-4911/looney-tunables-local-privilege-escalation-glibc-ld-so.txt
    - https://www.youtube.com/watch?v=1iV-CD9Apn8
    - http://www.openwall.com/lists/oss-security/2023/10/05/1
    - http://www.openwall.com/lists/oss-security/2023/10/13/11
  classification:
    cvss-metrics: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 7.8
    cve-id: CVE-2023-4911
    cwe-id: CWE-787,CWE-122
    epss-score: 0.0171
    epss-percentile: 0.87439
    cpe: cpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: gnu
    product: glibc
  tags: cve,cve2023,code,glibc,looneytunables,linux,privesc,local,kev,gnu

self-contained: true
code:
  - engine:
      - sh
      - bash
    source: |
      env -i "GLIBC_TUNABLES=glibc.malloc.mxfast=glibc.malloc.mxfast=A" "Z=`printf '%08192x' 1`" /usr/bin/su --help
      echo $?

    matchers:
      - type: word
        words:
          - "139"     # Segmentation Fault Exit Code
# digest: 490a0046304402202d08133fa6531aad4e00eb212908470e14839334ed5db3de00407ea2cee249660220021a38d5d167fb379028d9c9f8fecd46d3360fd546c566ad3767be0e9913cca4:922c64590222798bb761d5b6d8e72950